THE BLOOD-SERUM DIAGNOSIS OF TYPHOID FEVER. 163 



A drop of the blood to be tested is obtained from the finger 

 or lobe of the ear and allowed to dry on a clean slide. With 

 a platinum wire a few loopfuls of sterile water are mixed with 

 the dried blood and the same is diluted until about of the 

 same color as normal blood. One loopful of this blood mixt- 

 ure is added to 40 or 50 loopfuls of a bouillon culture of 

 the Bacillus typhosus twenty hours old, on a cover-glass, and 

 a hanging drop made in the usual way. In the course of a 

 half- to one hour, if the blood comes from a case of typhoid 

 fever of sufficient duration, not less than six or seven days, 

 cessation of motion and clumping of the bacteria in the 

 culture drop will have been completely effected. 



In the experience of the author in 'the Municipal Labora- 

 tory of New Orleans with more than 6000 cases, this test 



FIG. 65. 



Outfit used by the Municipal Laboratory of New Orleans for the collection 

 of blood for the typhoid fever test. 



has given satisfactory results. The plan, which is a modifica- 

 tion of the New York Board of Health method, is as follows : 



At the diphtheria depots blood slides are left with blank 

 forms giving directions (Fig. 65). 



Directions for Preparing Specimen of Blood. Clean thor- 

 oughly the tip of the finger or lobe of the ear, and prick with 

 a clean needle deep enough to cause several drops of blood to 

 exude ; two or three drops are then placed on the slide of the 

 outfit. Let the blood dry, then place the slide in holder, fill 

 out the blank form, and return to depot where obtained. On 

 the following day a report of the result of examination will 

 be mailed or telephoned to the attending physician. 



